New Yorkers need to know that the city will keep a close eye on the billions of taxpayer dollars it spends every year with corporations on costly, complicated contracts. They also need to know that when corporations try to cheat the city, those businesses will be held accountable.

That’s what we try to do at the Comptroller’s Office.

Audits done by my office assisted the U.S. Attorney’s Office in clawing back $466 million from the SAIC for that company’s mismanagement and fraud in the infamous CityTime scandal. That money went a long way toward balancing last year’s city budget.

Now, my office is demanding that Hewlett-Packard Corporation repay, related to its outrageous overbilling on the upgrade to the city’s 911 emergency call system.

That project was so woefully mismanaged, it is now many years behind schedule and $1 billion over budget. My auditors’ findings on HP were so disturbing that we turned the information over to the Manhattan District Attorney’s Office.

But that’s not all.

We also are asking the city to renegotiate its lease agreement with the Marriott Marquis Hotel, which may be the worst deal since Manhattan was sold for $24.

In 1998, the city’s Economic Development Corporation gave Marriott a sweetheart deal: In 2017, the Marriott Marquis can purchase the Times Square land it sits on from the city - one of the hottest pieces of Manhattan real estate - for a fire-sale price of $20 million. That’s ten cents on the dollar compared to the land’s value of $200 million today.

All told, that deal could cheat taxpayers out of $345 million if it’s not fixed.

The city needs to get all this money back, just like we did with CityTime. My office does what it can, but City Hall needs to do its share of the lifting.

Getting back from HP of what it owes the city and fixing the sweetheart deal the city granted Marriott could help restore the 20 fire companies, more than 30,000 childcare slots, and nearly 1,000 school teachers that face elimination in the upcoming year’s budget.

City Hall can’t turn back the clock and undo the gross mismanagement of these projects, but it can claw back taxpayer money. We cannot let corporations get away with ripping us off.